| 摘要 |
PCT No. PCT/AU91/00251 Sec. 371 Date Nov. 20, 1992 Sec. 102(e) Date Nov. 20, 1992 PCT Filed Jun. 13, 1991 PCT Pub. No. WO91/20176 PCT Pub. Date Dec. 26, 1991.A DC power supply for producing plasma for a DC arc torch. The DC power supply includes a controlled switch for coupling and decoupling a direct current source from the DC arc torch. The DC power supply also includes an inductance for supplying current to the DC arc torch when the direct current source is decoupled from the DC arc torch. A freewheeling diode is used to provide a current path from the inductance to the DC arc torch. A switch driver drives the coupling and decoupling of the controlled switch at a particular frequency and at a variable duty cycle. A feedback circuit varies a variable duty cycle of the switch driver in response to the amount of current detected flowing to the DC arc torch. |
